Torquer motors for stabilizing sensitive apparatuses inside structures from translational and rotational vibrations are known. Such motors typically provide corrective torques to stabilizing members coupled between the vibrating structure and the sensitive apparatus in response to signals from gyroscopes and angular accelerometers mounted on the sensitive apparatus. In one illustrative example, the sensitive apparatus is a package of optical and electronic sensor equipment, and the vibrating structure is a gimbal mounted on a surveillance aircraft.
U.S. Pat. Nos. 4,033,541, 4,315,610, 4,443,743 and 4,498,038 are emblematic of the prior art approaches to such motors, the contents of which are incorporated herein by reference.
FIGS. 1A and 1B illustrate one example of a coil pair for a torquer motor in accordance with prior art approaches. In FIG. 1A, one coil 102a of a two-coil pair for use in a torquer motor is illustrated. In one example, coil 102a is about 0.125 in thick and 1.27 in wide. As further shown in FIG. 1A, coil 102a is comprised of copper windings 104a, each measuring about 0.027 in. on the diameter for example, wound in a counter-clockwise direction in coil 102a. It should be noted that, although only a few windings are shown, there can be, and typically are several hundred or more. It should be further noted that coil 102a may further comprise an epoxy to bind the windings together as is known to those skilled in the art.
FIG. 1B illustrates coil pairs 102a and 102b comprising a coil pair 110 for a torquer motor according to one example of the prior art. As shown in FIG. 1B, coil 102b is mounted atop coil 102a such that their respective windings 104a and 104b overlap each other in orthogonal directions in a common plane direction so as to define an active area 106. The corners of coils 102a and 102b are further typically mounted to an inner gimbal payload structure (not shown, i.e. the apparatus to be stabilized) so as to correct for vibrations induced to the structure and stabilize the apparatus. In a manner consistent with the prior art patents referenced above, the active area 106 is further disposed between the poles of a magnetic element (not shown), the magnetic element being mounted to an outer gimbal (not shown, i.e. the vibrating structure). In particular, depending on signals from gyroscopes and accelerometers (not shown), the amount of relative current in windings 104a and 104b is adjusted so as to control the force resulting from the cross product of the current in the active area 106 and the magnetic field between the poles of the magnetic element, and thus cause relative corrective movement between the vibrating structure and the apparatus to be stabilized.
Although coil pair 110 has certain advantages for use in a torquer motor, there remain problems. First, the mounting of the motor at the corners is difficult because the dimensions of the copper wind are difficult to control within the tolerances of a machined bracket. In addition, the small bond areas at the corners of the coils do not provide rigid mounting. The lack of rigidity causes ringing that is fed back into the system. Still further, the size of the mounted area is limited, such that the heat that is generated in the coils through I2R losses cannot be effectively cooled by conduction to the bracket.
Moreover, there are certain problems with the conventional torquer motor that have particular consequences for gimbal applications. For example, it can be difficult and very time-consuming to physically make the coils in an optimal fashion because of how the copper windings must arranged to comprise the coils. These winding inefficiencies can lead to inefficiencies in operation of the motor. In particular, for a coil that is used to compensate for vibrations in an important direction such as azimuth, it is very important for the windings in the corresponding coil to be efficient and near optimal. The conventional design, however, does not lend itself to such optimization.
Accordingly, it would be desirable if a novel concept for a torquer motor could be introduced that still provides the required high torque stabilizing forces, but does so with a design that is more compact, easier to mount, has greater structural rigidity, allows for better heat conduction to a mounting bracket or other structure, and leads to optimal performance in certain applications.